A multi-carrier technology is a technology of sending data to a user equipment (User Equipment, hereinafter referred to as UE) through multiple carriers simultaneously. In a multi-carrier system, a compressed mode is introduced for implementing inter-frequency measurement or inter-system measurement in frequency division duplexing (Frequency Division Duplexing, hereinafter referred to as FDD). The inter-frequency measurement refers to network measurement conducted when the working frequency of a UE changes in the same communication system. The inter-system measurement refers to network measurement conducted when the network system where a UE works changes, for example, network measurement performed when the UE is handed over between network systems using different access technologies, for example, from a global system for mobile communications (Global System for Mobile Communications, hereinafter referred to as GSM) to a wideband code division multiple access (Wideband Code Division Multiple Access, hereinafter referred to as WCDMA) system.
The compressed mode indicates that one receiver can only work on one receiving and transmitting frequency at a time. To measure signals on another frequency, the receiver must stop working and switch to a target frequency before performing measurement. To ensure normal transmission of downlink signals, network device needs to transmit original signals within a remaining transmission time. This is a downlink compressed mode. When measurement frequency and uplink transmitting frequency are close, transmission of uplink signals needs to be stopped simultaneously to ensure the measurement effect. This is an uplink compressed mode. Activating a compressed mode for a UE and network device may affect data receiving on the current frequency. Therefore, activation of the compressed mode should be avoided as much as possible.
For a user equipment (User Equipment, hereinafter referred to as UE) that supports multiple carriers over one frequency band (hereinafter referred to as band), only one receiver is required. For example, the bandwidth of the receiver is 10 M, and the bandwidth of each carrier is 5 M. Accordingly, the UE does not need to activate the compressed mode when performing the inter-frequency measurement on adjacent carriers, and the UE needs to activate the compressed mode when performing the inter-frequency measurement on non-adjacent carriers. For a UE that supports multiple inter-band (hereinafter referred to as inter-band) carriers, two receivers are required and the two receivers are working on different bands. The UE may work on some band combinations. Therefore, the UE may simultaneously measure two bands in a band combination without activating the compressed mode. For the band of each receiver, similar to the situation where only one receiver is used, the UE may perform inter-frequency measurement on adjacent carriers without activating a compressed mode.
In the prior art, a UE may report capability information for inter-frequency measurement without compressed mode to network device. The network device configures an inter-frequency neighboring cell list in measurement control and indicates the UE that the UE may perform measurement without compressed mode on the frequencies of cells corresponding to an adjacent frequency index (hereinafter referred to as adjacent frequency index) in the inter-frequency neighboring cell list. When performing measurement on adjacent frequencies, the UE needs to check whether the frequencies to be measured are the frequencies indicated by the adjacent frequency index. If yes, the UE performs measurement without compressed mode on the adjacent frequencies. If not, the UE waits for the compressed mode.
However, in the prior art, when a UE performs measurement without compressed mode on adjacent frequencies, a problem of measurement failure frequently occurs.